Examine source code of Tab Close on Escape

{
  "manifest_version": 2,
  "name": "Tab Close on Escape",
  "version": "1.0",
  "description": "Closes the current tab when the Escape key is pressed",
  "permissions": [
    "tabs"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "tabcloseescape@example.com",
      "data_collection_permissions": {
        "required": [
          "locationInfo"
        ],
        "optional": [
          "technicalAndInteraction"
        ]
      }
    }
  }
}